1. Field of the Invention
The present invention relates to braking force control apparatus and method for an automotive vehicle which are capable of stably traveling the vehicle during a turning.
2. Description of the Related Art
A traction control system (TCS) and sideslip prevention system (or vehicular dynamic control (VDC) system) have been well known as a vehicular system which is capable of stably turning the vehicle. Both of the systems have aimed at vehicular stabilization. The former system is to increase stability by securing a lateral force of driven wheels through a suppression of a driving force and provision of a braking force with drive slips detected. The latter provides the braking force for each road wheel independently to stabilize a vehicular behavior in a case where a sideslip angle of the vehicle and a yaw rate are in excess of each corresponding predetermined value. However, under a situation such that a drive slip is not developed, or under a situation that the vehicle enters into a turning, when a vehicle speed thereof exceeds a limit speed set with a radius of the turn taken into account, each of the above-described stabilization systems has not been operated until a, so-called, drift-out motion or spin motion is provoked. A Japanese Patent No. 2600876 issued on Apr. 18, 1997 (which corresponds to a Japanese Patent Application First Publication No. Heisei 2-171373 published on Jul. 3, 1990) exemplifies a previously proposed braking force control apparatus. In the previously proposed Japanese Patent Application first Publication disclosed in the above-described Japanese Patent, a vehicular turning state variable of the vehicle is detected, in a case where the detected turning state variable approaches to a value set with respect to a limit turning state variable up to which the vehicle can stably be traveled, a target deceleration required to travel the vehicle maintaining a stability during the turning of the vehicle is calculated, and the braking force is applied to the vehicle which achieves the target deceleration is provided for the vehicle.